#pragma once

#include  "iostream"
#include  "vector"
#include  "stack"
#include  "unordered_map"
#include   "queue"

using namespace std;

/*
 * 37. 解数独
困难
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编写一个程序，通过填充空格来解决数独问题。

数独的解法需 遵循如下规则：

数字 1-9 在每一行只能出现一次。
数字 1-9 在每一列只能出现一次。
数字 1-9 在每一个以粗实线分隔的 3x3 宫内只能出现一次。（请参考示例图）
数独部分空格内已填入了数字，空白格用 '.' 表示。
 *输入：board = [["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4",".",".","8",".","3",".",".","1"],["7",".",".",".","2",".",".",".","6"],[".","6",".",".",".",".","2","8","."],[".",".",".","4","1","9",".",".","5"],[".",".",".",".","8",".",".","7","9"]]
输出：[["5","3","4","6","7","8","9","1","2"],["6","7","2","1","9","5","3","4","8"],["1","9","8","3","4","2","5","6","7"],["8","5","9","7","6","1","4","2","3"],["4","2","6","8","5","3","7","9","1"],["7","1","3","9","2","4","8","5","6"],["9","6","1","5","3","7","2","8","4"],["2","8","7","4","1","9","6","3","5"],["3","4","5","2","8","6","1","7","9"]]
解释：输入的数独如上图所示，唯一有效的解决方案如下所示：
 *https://leetcode.cn/problems/sudoku-solver/description/
 *
 * */
bool isVaild(vector<vector<char>> &board, int row, int col, char val) {
    int rowMax = board.size();
    int colMax = board[0].size();
    //lie判断
    for (int i = 0; i < 9; ++i) {
        if (val == board[i][col])
            return false;
    }

    //hang判断
    for (int i = 0; i < 9; ++i) {
        if (val == board[row][i])
            return false;
    }
    // 九宫格判断 例如index=3 那么开始就是3 index=4开始就是3
    int startRow = (row / 3) * 3;
    int startCol = (col / 3) * 3;
    for (int i = startRow; i < startRow + 3; ++i) {
        for (int j = startCol; j < startCol + 3; ++j) {
            if (board[i][j] == val)
                return false;

        }
    }

    return true;
}

bool dfs(vector<vector<char>> &board) {
    int rowMax = board.size();
    int colMax = board[0].size();
    for (int i = 0; i < rowMax; ++i) {
        for (int j = 0; j < colMax; ++j) {
            if (board[i][j] == '.') {
                for (int k = '1'; k <= '9'; ++k) {
                    if (isVaild(board, i, j, k)) {
                        board[i][j] = k;
                        if (dfs(board))
                            return true;

                        board[i][j] = '.';
                    }

                }
                return false;//我擦必须这边返回flase
            }

        }
    }

    return true;
}

void solveSudoku(vector<vector<char>> &board) {

    dfs(board);


}